Abstract: A opto-electric combination lock is described in which a single light emitting diode provides light to a phototransistor through a path which can be created by pulling and rotating a plurality of plunger assemblies. Each of the plunger assemblies have an opening therethrough which is placed in alignment with the path if that particular plunger assembly is pulled and rotated by the combination amount. The lock includes a switch for enabling the power supply only upon the pulling of a particular one of the plunger assemblies and further includes circuit means for actuating an event such as unlocking a door upon the creation of the light path.